Method of extruding a weatherstrip having a pile strip

ABSTRACT

Method of making a weatherseal is made by extruding a resin base with a relatively thick, flat support portion and a relatively thin, portion U-shaped in cross section and joined to opposite side edges of the support portion to arch over the center of the support portion. While the resin material is still plastic, a pressure differential expands the U-shaped portion to reduce the thickness of the walls of the U-shaped portion, and then each side of the U-shaped portion is cut at a predetermined distance from the support to leave a pair of thin, spaced-apart resilient fins. Then fibrous pile material is secured to the support between the fins to form a double-fin, pile weatherseal.

This is a division of application Ser. No. 446,301, filed Feb. 27, 1974,now U.S. Pat. No. 3,923,576.

THE INVENTIVE IMPROVEMENT

Pile weatherseals having associated sealing fins running longitudinallywith the pile material have generally known advantages. Such sealingfins have been applied to pile weatherseals in various ways, and theyhave been located in the center of the pile, and along both edges of thepile. The invention involves recognition of a simpler and moreeconomical way of making a finned pile weatherseal having fins extendingalong both side edges of the pile. The invention aims at economy, fasterand simpler production methods, and quality construction of theresulting weatherseal.

SUMMARY OF THE INVENTION

In making the inventive weatherseal, a resin base is extruded with arelatively thick, flat support portion and a relatively thin portionU-shaped in cross section and joined to opposite side edge regions ofone face surface of the support portion and arching over the supportportion. While the resin material is still plastic, a substantiallylower pressure outside the U-shaped portion than inside the U-shapedportion expands the U-shaped portion away from the support portion andreduces the thickness of the wall of the U-shaped portion, and the resinis set with the U-shaped portion expanded. Then each side of theU-shaped portion is cut off at a predetermined distance from the supportportion to leave a pair of thin, spaced-apart, resilient fins extendingaway from the surface of the support portion, and a fibrous pilematerial is secured to the support portion between the fins. A similarresult can be achieved by a cross-head extrusion of a pile strip with aresin base having a U-shaped portion arching over the pile and expandedand cut away to form fins.

DRAWINGS

FIGS. 1 and 2 are schematic diagrams of alternative preferred processesfor practicing the invention and schematically showing cross-sectionalviews of the product at each stage of the process; and

FIGS. 3-5 are end elevational views of three preferred forms of productsproduceable according to the invention.

DETAILED DESCRIPTION

FIGS. 1 and 2 show two alternative processes according to the inventionfor producing double-fin, pile weatherseals such as shown in FIGS. 3 and4. Each of the weatherseals includes a fibrous pile material, a fin oneach side of the pile, and a resin base, and each is made in indefinitelengths that can be cut and fitted in place to meet many weathersealrequirements. Such weatherseals are commonly used around doors andwindows, and the pile material provides resilience and a low-friction,long-wear-life sealing surface, and the fins on opposite sides of thepiles wipe against the surface to be sealed and make the seal moreairtight and watertight than pile alone could accomplish. The processesillustrated in FIGS. 1 and 2 are described below.

Beginning with the process of FIG. 1, a resin base is formed by extruder10 to have the illustrated thick, flat support portion 11, and arelatively thin portion 12 U-shaped in cross section and joined toopposite side edge regions 13 of support portion 11 to arch over supportportion 11 as illustrated. While the resin material is still plastic, apressure-differential creating device 14 produces a substantially lowerpressure outisde U-shaped portion 12 than inside U-shaped portion 12,either by reducing the outside pressure or increasing the insidepressure, to expand U-shaped portion 12 as illustrated. Since supportportion 11 is relatively thick and strong compared to U-shaped portion12, support portion 11 does not deform under the pressure differential,but U-shaped portion 12 is substantially expanded as illustrated toreduce the thickness of the wall of U-shaped portion 12. Then a cutter15 cuts both sides of U-shaped portion 12 at a predetermined distancefrom support portion 11 to leave a pair of thin, spaced-apart, resilientfins 16 extending out from one face surface of support portion 11 asillustrated. Then a device 17 secures pile material 18 in place betweenfins 16 as illustrated to complete a weatherseal.

Many variables can be made in the above-described process, including theresin material selected, the dimensions of support portion 11 andU-shaped portion 12, the extrusion speeds and temperatures, the pressuredifferential applied to expand U-shaped portion 12, the method ofcutting in device 15, the height of the cut of fins 16, the type of pilematerial 18, and the manner of securing it in place. The choices forthese variables are generally known to those skilled in the art.

In the method of FIG. 2, a strip of pile material 19 having a base 20 ispre-prepared in device 21 in supply lengths available for feeding tocross-head extruder 22 which cross-head extrudes a base over pile 19.The base includes relatively thick, flat support portion 11 and U-shapedportion 12 as previously described with U-shaped portion 12 secured toside edge regions 13 of support 11 and arching over pile 19. Thenpressure differential device 14 expands U-shaped portion 12 to arch ithigher over pile 19 and reduce the thickness of the walls of U-shapedportion 12. Then cutting device 15 cuts U-shaped portion 12 asillustrated to leave thin, resilient fins 16 on opposite sides of pilematerial 19. The expansion of U-shaped portion 12 stretches fins 16 to aresilient, thin sheet form that is optimum for fins 16 and is thinnerthan could be practically extruded as an original shape.

FIG. 3 shows pile material 23 formed by flocking fibrous pile filaments23 in place in the region between fins 16 on support portion 11. Thismethod can be used in conjunction with the process of FIG. 1 as a meansfor placing pile between fins 16. Separate pile strips 24 withassociated bases 25 as shown in FIG. 4 can be secured between fins 16 asthe last step of the method of FIG. 1, or can be fed to a cross-headextruder for practicing the method of FIG. 2.

FIG. 5 shows a weatherseal 30 made according to the cross-head extrusionmethod of FIG. 2 having support portion 11 under base 20 of pile 19, andU-shaped portion 12 arching over pile 19. A pressure differential isused to expand U-shaped portion 12 slightly above pile 19 as illustratedin FIG. 5 rather than the substantially greater expansion illustrated inthe method of FIG. 2, and then U-shaped portion 12 is left uncut in thefinal weatherseal 30 so that U-shaped portion 12 provides a low-frictionsealing engagement surface with high resiliency to accommodate varioussealing surfaces, and pile 19 provides resilient support preventingU-shaped portion 12 from collapsing. U-shaped portion 12 then need beexpanded only slightly to clear pile 19 by a small amount to produce thedesired flexibility, and U-shaped portion 12 makes pile 19 airtight andwatertight and provides a highly resilient surface to be pressed againsta surface to be sealed by the resilience of supporting pile 19. Themethod of FIG. 2 with a slight modification then produces a newweatherseal 30 having many of the advantages of resilient pile and addedadvantages from enclosing the pile in resilient, U-shaped portion 12.

Persons wishing to practice the invention should remember that otherembodiments and variations can be adapted to particular circumstances.Even though one point of view is necessarily chosen in describing anddefining the invention, this should not inhibit broader or relatedembodiments going beyond the semantic orientation of this applicationbut falling within the spirit of the invention. For example, thoseskilled in the art will appreciate the many variations in materials,structures, and method steps that can be made in putting the inventivemethod into practice.

I claim:
 1. A weatherseal making method comprising:a. preparing a long,thin strip of pile material; b. cross-head extruding a resin base havinga relatively thick, generally flat support portion formed on the back ofsaid pile strip and a relatively thin portion U-shaped in cross sectionand joined to opposite side edge regions of one face surface of saidsupport portion and arching over said pile strip; c. while said resinmaterial is still plastic, producing a substantially lower pressureoutside said U-shaped portion than inside said U-shaped portion toexpand said U-shaped portion away from said support portion and reducethe thickness of the wall of said U-shaped portion; and d. setting saidresin material with said U-shaped portion expanded over said pile strip.2. The method of claim 1 including cutting each side of said U-shapedportion at the approximate height of said pile from said support portionto leave a pair of thin, spaced-apart resilient fins extending away fromsaid support portion on opposite sides of said pile strip.